(1) The maximum thickness of the growth layer at which quantum dots begin to form naturally is derived theoretically for the heteroepitaxial growth of the semiconductor layer whose lattice constant differs from that of the semiconductor substrate. The theoretical results agree well with the experimental resutls of InAs/GaAs, InP/GaP, ans SiGe/Si. (published in Thin Solid Films)(2) The optimum thickness of GaAs layer for the InAs/GaAs quantum-dot stacked layer is experimentally determined. (published in Journal of Electronics Materials)(3) The disordered effects which causes the enhancement of luminescence intensity and the red shift of luminescence peak have been observed in the spontaneously ordered GaInP/GaAs. (published in Journal of Applied Physics) Although the luminecence enhancement and red-shift were observed in the ordered states in disordered matrix, the phenomena can be interpreted with the effects by thedisordered states in ordered matrix(4) The disordered quantum wire in w
… Morehich the wire width, thickness, and composition are disorderly fabricated exhibits the effects of luminescence enhancement and red-shift. (published in Applied physics Letters)(5) Remarkable progress in growth technology is required to fabricate a high density of InAs/GaAs quantum dot. Howerer, in the InGaN/GaN quantum well which is grown at the low temperature and/or with a high In composition rate, the dot-like quantum structure is formed. It exhibits the luminescence enhancement and the red-shift. (submitted to the International Conference on Physics of Semiconductors)(6) The final aim is to search new quantum optoelectronic properties such as the luminescence enhancement and the red-shift by disorderly stacked layer of disordered quantum dots (d-QDs) fabricated by the Stmaski-Krastanov growth mode. However, scientific and technological achievements by this research project can be stated as that the properties which were expected by disorderly stacked layer of d-QDs were observed also by the disordered quantum wires, the spontaneously ordered semiconductors, and the quantum well with compositional fluctuations caused by a large lattice-mismatching. Further development for the quantum optoelectronic properties can be expected by the improvement of the growth technology6.当初InAs/GaAsのStranski-Kurastanov(S-K)成長姿態による不規則積層量子ドットの新光量子物性の探索にあった。しかし不規則量子細線とその不規則による新光量子物性の実証、また組成が整数比に近い半導体、格子定数差の大きい半導体の組成ふらつきによっても実現可能であることを実証し、それらに対する知見を得たことは、本研究の成果である。今後は、成長技術の向上によりより一層の強い光量子物性を得ることができると考える。 Less